The existing circuit breaker, particularly a miniature circuit breaker realizes its wiring function through the reliable connection between terminals and loop wires. The circuit breaker is mainly used for protecting end of the lines in the early stage. With regard to this loop, it may be obtained and applied as long as one wiring function of the wire is realized. With the enlarged application range of the circuit breaker, branched wiring is usually performed on each phase of a circuit breaker in a next-stage parallel system or parallel lines due to the need of distribution of power system or circuit design. For example, when the line is required from the outlet end of the master switch into multiple parallel branches, it usually employs a manner of performing parallel wiring on the same phase terminals of the circuit breakers on these parallel branches. After this wiring manner is employed, the type of wires that can be connected to the circuit breaker is increased from one type initially to two types. The increased wiring type causes various permutation and combination of wires that may be connected to the existing circuit breaker. At present, the wires commonly used by the circuit breaker in the market include: multi-strand wires, single-strand wires, bus (bus bar) and wires having annular joints used for realizing quick wiring. Therefore, a circuit breaker that can realize the wiring function of combination of any two commonly used wires will adapt for the market demands more quickly.
In the existing technical field, the following technical solutions are employed to realize the wiring function of the circuit breaker.
The first technical scheme, as shown in FIG. 1, wherein wiring boards and terminals are mounted within a housing of a circuit breaker. The terminal includes a wire trap that can generate relative movement with the wiring board, and a screw that is in screw-thread fit with the wire trap. A wire is connected between the wire trap and the wiring board, and is fastened through the screw to realize the wiring function of the circuit breaker.
The second technical scheme, as shown in FIG. 2, which is the most common wiring manner of the circuit breaker at present. On the basis of the first technical solution, a second wiring board is added on the movement direction of the wire trap. This wiring board is equipotential with the original first wiring board. The screw in screw-thread fit with the wire trap traverses said second wiring board, and the bus (bus bar) wiring function is realized through the screw and the second wiring board.
By carefully comparing the existing two technical solutions, it is not difficult to find that if the second technical solution is taken as the basis, the bus (bus bar) function used in the first technical solution can also be designed. Compared with the first technical solution, the second technical solution separates the bus (bus bar) wiring function from the conventional wiring function and makes the two functions independent mutually through the two wiring boards. This enables the second technical solution to realize all the wiring functions of the first technical solution while realizing the bus (bus bar) wiring function; but, it is inevitably to make the terminals and wiring board structure relatively complicated.
Moreover, in the foregoing two technical solutions, only one wiring space is formed between the wiring board and the wire trap, and a hybrid junction of single-strand wires with different diameter cannot be realized on the combination of the wires that can be connected.
Meanwhile, none of the two technical solutions can realize to use the wires having annular joints in quick wiring, and only the bus (bus bar) wiring function can be used.
Further, as described in the foregoing two technical solutions, after the circuit breaker finishes the wiring of the wires, it is not difficult to image that when multi-pole circuit breaker connecting wires, the exposed wire end is outside the circuit breaker housing, and the electrical clearance and the creepage distance of two adjacent wires are very small. If the wires are short connected, it will necessarily bring security risks. When using the bus (bus bar) wiring, although short circuit between adjacent poles does not exist, the electrical clearance and the creepage distance are too small; during a long term usage process, security risks of use in later period will also be brought due to the reduced performances of insulating materials.